1. Field of the Invention
The present invention relates to a device for cleaning wire rope, such as those used in the elevator industry.
2. Description of the Related Art
The conventional manner of operating elevators is by raising and lowering a typically enclosed platform, the elevator using an electronically controlled, variable speed hoisting machine. The platform is connected to cabling which moves by the hoisting machine. The cabling is typically comprised of a plurality (e.g., five or six) of steel ropes. Each of the steel ropes is typically fabricated from multiple strands, and each strand contains multiple individual wires that are spirally wrapped around a fiber core to form lengths of cylindrical traction steel. The size or diameter of the rope used on each elevator is, typically, determined by engineering specifications regarding load capacity, elevator speed and vertical height.
Drawing FIG. 1 hereof is an elementary representation of a conventional elevator installation 10. A plurality of separate ropes 100 extend from the top of the elevator car 110, over the hoisting machine 130 and the deflector sheave 120, to the top of the counterweight 140. The deflector sheave 120 is positioned laterally away from the elevator car 110 to offset the car from the counterweight 140, so that each will not interfere with the vertical travel of the other. The hoisting machine 130 is typically installed at the top floor or at an intermediate floor 150 of the building and is supported there by legs 135 or a pedestal.
As shown in FIG. 1, at one side, the car side, the ropes 100 extend off the hoisting machine 130 perpendicular to the floor 150. At the other sheave side of the hoisting machine 130, the ropes 100 are guided obliquely to the floor 150 from the sheave 120, which causes the above-described offset of the elevator car 110 and the counterweight 140.
During normal operation of the elevator, the ropes 100 become coated with contaminants that adhere to the individual wires of which the body of each wire rope 100 is comprised. These contaminants include building grime, air borne dust, and rust produced by external sources of moisture. Local area safety codes typically require that the wire ropes 100 be periodically inspected, cleaned and lubricated to prevent deterioration and possible operating danger. Wire ropes have usually been cleaned by hand, using rags, cable lubricant and wire brushes. Such rope maintenance is often performed during normal elevator operation. As the wire ropes 100 may travel at speeds ranging from 500 to 1600 feet/minute, manual cleaning is dangerous.
Various types of non-manual wire rope cleaning devices are known in the art. For example, U.S. Pat. No. 5,386,882 discloses an apparatus for mechanically holding a pair of wire brushes on either side of the perpendicular path of ropes 100 in FIG. 1, hereof. FIGS. 2A and 2B hereof illustrate a U shaped holder 175 that can be bolted directly to the floor 150 in an area, corresponding to a hole 160 shown in FIG. 1. In the embodiment shown in FIGS. 2A and 2B, the holder 175 is not adjustable, and only wire brushes of a precise size work properly in the apparatus.
Another known wire brush cleaning apparatus 185 is described in U.S. Pat. No. 5,036,563 illustrated by FIGS. 3A and 3B hereof. Rotating cylindrical brushes 180 are placed on a shaft offset from the rope 100. The apparatus 185 taught by the U.S. Pat. No. 5,036,563 patent is inefficient, partially because the brushes 180 rotate at a speed comparable to the rotation speed of a drive sheave, and in the same direction of movement thereby resulting in poor performance.
U.S. Pat. No. 5,784,752 discloses a wire brush cleaning device 190 that comprises a lateral cylindrical brush 195 rotating on a center shaft within a metal enclosure 192 as illustrated in FIGS. 4A and 4B hereof. This device is believed to be inefficient for the same reason as the previously described device. This is because rotating brush 195 does not provide effective scrubbing action across the surface of a wire rope 100. An incorporated scraping bar in this device removes only desiccated deposits. Moist debris embeds deeply within the core of the brush 195 and negates the effect of the cleaning bar.
FIGS. 5A, 5B and 6 illustrate an adjustable brush cleaning apparatus 194 disclosed in U.S. Pat. No. 6,470,528. As shown in FIGS. 5A, 5B and 6, brushes 196 are mounted to a frame 198. The angle of brushes 196 can be adjusted to match the angle of ropes 100. One shortcoming of apparatus 194 is that only the angle of the brushes 196 is adjustable.
A brushless cleaning device disclosed in U.S. Pat. No. 5,791,011 uses a length of rolled material draped over the drive sheave and wire ropes. The fabric wipes the surface of the ropes as the ropes rotate with the sheave. One negative aspect is heat created by friction between the cleaning fabric and the rotating ropes. This heating is a possible cause of combustion which danger is compounded by the embedded, oil laden contaminants on the rope.
In all of the prior wire brush cleaning devices known in the prior art, the brushes are abraded, producing metal dust which may be drawn to magnetized parts of the hoist machine. Cracks in dry insulation around motor fields or direct contact with the machine armature can cause a short circuit due to the high current needed to operate the hoist machine. Additional pressure exerted by non-adjustable wire brush devices only increases dust produced during extended use.